With the increasing global energy demand, development of devices that directly convert thermal energy into electricity, often termed thermoelectric devices, are receiving particular attention. Lead telluride and bismuth telluride are materials that have been well studied with regard to their thermoelectric properties, yet such materials have met with limited acceptance owing to problems associated with material synthesis. Theoretical calculations and molecular beam epitaxy investigations of these materials suggest that considerable improvements in thermoelectric properties for these materials can be achieved by the synthesis of such material having nanometer sized domains (1-6).
Conventional bulk lead telluride and bismuth telluride have been prepared through solid-state reactions at elevated temperatures, through pyrolysis of organometallic precursors, or through gas-phase reaction of metal atoms and hydrogen telluride. The lead telluride having nanometer size domains has been synthesized through solvothermal and organic-ligand-assisted methodologies (7-8). Unfortunately, existing methodologies for producing nanometer size domains of lead telluride are conducted at high temperature using toxic organic solvents and tend to produce material in low yields.
Thus, there exists a need for a synthetic procedure to produce nanocrystalline metal tellurides and in particular lead telluride and bismuth telluride by a process amenable to large scale production. Additionally, there exists a need for a densified metal telluride mass amenable for use within the context of a thermoelectric device.